Gas indicator



Patented Sept. 5, 1944 UNITED STATES PATENT OFFICE spacial: 321 ,139

9 Claims.

This invention relates to gas indicators and more particularly to apparatuses for indicating the amount of carbon dioxide (CO2) gas in the products of combustion in furnaces, in the exhaust of engines, and the like.

The principal object of the invention is the provision of a new and improved device for indicating the percentage of CO2 gas in specimens of smoke, engine exhaust, and the like, and that is small enough to be carried in the pocket and that is substantially accurate.

A further object of the invention is the provision of a pressure operated CO2 testing device so constructed thatwhether the device is in operation or not there is no danger of spilling the liquid in the event the apparatus is tipped over.

A still further object of the invention isthe provision of a new and improved apparatus for indicating thepercentage of CO2 in a given quantity of mixed gases.

Another object of the invention is the provision of a new and improved apparatus for indicating the amount of present in smoke, engine exhaust and the like in which a caustic solution is employed, not only as the absorbing me-. dium for the C09 gas but also as the gauge or indicating liquid.

A further object of the invention is the pro- .larged scale; and

Fig. 3 is a section on the line 3-3 of Fig. 2.

Referring now to the drawing, the reference character I!) designates a block of material which may be of a single piece or sectional, as desired. The block has two columns therein intercommunicating at their lower ends. Asshown, these provide an annular shoulder l4 for'limiting the downward movement of a plunger slidably mounted, as will presently appear;

The lower ends of the arms l2 and Hare connected by a transverse bore I U, The arm 12 of the bore ll may be made by first drilling the block from its upper end with a drill having adiameter of the lower end of the arm i2, then counterboring with a larger diameter drilland afterwards further counterboring the outer or upper end of the counterbore to form a section of the bore of further increased diameter, as shown at H. The inner surface'of the counterbore 11 is threaded for receiving a threaded plug 18 in which is adapted to be mounted a combined intake and discharge valve l9 and an operating stem 2| for the plunger IS. The cross bore I6 is formed by drilling from the side, counterboring the outer end of the cross bore and threading the same for receiving a threaded stud 22 for closing the cross bore l6.

bore is counterbored to form a reservoir or chamber 23 of large diameter, as is shown in Figs. 1 and 2. The outer end of the chamber 23 is counterbored and the inner surface threaded'as at 24 for receiving a screw threaded plug 25. The plug 25 has an axial opening as at 28 through which a valve stem 2} i adapted to slide. The opening 26 is enlarged, that is, it is counterbored at its upper end as at" 3B for forming an annular shoulder as shown at 28. The enlarged bore 23 constitutes an air reservoir under atmospheric pressure for forcing the liquidin the arm I: of the L-shape bores when the caustic reacts on the C02 within the chamber 35, as will presently appush button 29 at its upper end and a spring 3| is interposed between the shoulder 28 and the knob 29 for normally holding the stem in its uppermost position. Attached to the lower end of columns are in the form of a U-shaped bore I l.

having an arm l2 and an arm". The arm [2 is of very much larger diameter than the arm l3. The block ill is preferably, though not necessarily, transparent and 'in the form of the construction shown, is made or molded from tr'ans-' parent plastic material.

The bore H has its intermediate portion 9 of the valve stem 21 is a valve orvalvehead 32 and interposed between the valve head 32 and the lower end of the stem is a sealing washer 33 of suitable material not afiected by the liquid employed in the U-bore and which is adapted to seatagainst the lower end of the plug 25 for clos-- ing the opening 28, as shown more clearly in Fig. 2 of the drawing. A passage 34 extending'between the enlarged opening 30 and the exterior of the block 10 is provided for the passage of air therethrough when the valves l8 and 32 are open for. equalizing the pressure on the two armsof slightly larger diameter than the lower end to the U-shaped borel The arm I3 is of very small diameter and the In determining the amount of CO: in the combustion gases, it is necessary to provide means whereby the gas to be tested will displace all of the air in a chamber 35 formed between the up per end of the plunger l5 and the lower end of the plug l8 before the combustion gases are ex-- posed to the action of the absorbent liquid. The

. mechanism for introducing the combustion gases terial, such as metallic or mineral wool 55, or

the like, that is not aflected by the caustic liquid, for increasing the surface so asto increase the exposure of the liquid to the gas. The wool is held in position in the head by a pin 56, or the like, extending across the lower end of the plunger,

The upper end 51 of the' plunger I5 has a central threaded opening 58 of small diameter within which is threaded a downwardly extending stud 59 of a plate member Bl which has an axial opening 50 of ,smallbore. The diameter of the bore or opening 50 is small so that there will be little or no movement of gas downward through the opening while the plunger is at rest. It is large enough, however, for the gas to pass through when the plunger i elevated.

is provided with an opening [0 in which a tool may be inserted for jamming the threads of the valve head to prevent accidental loosening of the valve head. A washer 42, of suitable material,

forming a seal, is interposed between the head 41 and the lower end of the plug ii for engag ing the plug for closing the opening 36. The valve stem 39 is provided with an intake passage which comprises a bore 43 extending through the upper portion of thevalve stem and downwardly to a point adjacent to the valve head but spaced above the same where it turns laterally and terminates at the surface of the stem at 60. as clearly shown on the drawing.

The valve stem is also provided on one side, preferably opposite the opening Bil, with a discharge passage 44 which may be formed by a cutaway portion on the side of the valve, as shown at 45 in Fig, 3. Gas is adapted to enter the chamber above'the plunger through theopening 80 and air or the gas is adapted to be discharged through the. passage 44.

hose which constitutes a discharge of a small The upper end of the valve stem 39 is screw threaded and a. fitting 48 of the gas to be tested. i

- videdfor sealing the opening 31 against the es-' cape of gas along said stem.-

Interposed between the plate member 6| and the end 51. of the plunger I5 is a wiper 52, of suitable material not aifected by the gasor caustic liquid, whichis clamped in position'by the plate member 6|. The wiper is adapted to clean the walls of the chamber 35 when the plunger is raised and lowered by the stem 2| extending through the plate and wiper and secured to the upper end of the plunger. Without this wiper, more or less of the caustic will adhere to the walls after a-testhas been made to seriously affect a following test. In other words, the reaction of this residue on the, incoming gas will seriously interfere with obtaining a pure sample The stem 2| extends upwardly through an opening 31 in the plug 18 and terminates in a knob '63, or the like, for convenience in manipulating the'stem 21. A suitable gland 64 is pro- A suitable scale is provided on the block In for indicating the percentage of CO: in a sample of gas tested. The scale may be read through pump, not shown, the intake of which is adapted to be placedin the stack for obtaining a sample gas to be tested, as is u ual in such constructions.

Appropriate means are provided for holdin the valve in its closed position. Any suitable.

means may be employed for this purpose. In'the form of the invention shown, the plug is is counterbored as-at 49 and is screw threaded at its lower end for receiving the threaded end of a sleeve SL. The sleeve 5| may, if desired, be provided with an opening 52 in its side wall .opposite the passage 44 through which air displaced in the chamber 35 may escape. A spring 53 is adapted to seat on a shoulder 54 formed on the lower end of the sleeve 5| and has its opposite end engaging the fitting 46 for normally holding the stem in its uppermost position so as to close the valve Suitable means are provided for separating the absorbent liquid from the gas to be tested during the process of. injecting a sample of the gas into the chamber- 35 and for mixing the gas with the absorbent liquid after the same has been trapped.

'In the form of the construction shown, the plunger 15 is cylindrical and closely tits the-intermediate section of the arm I! ofthe bore, as shown in Figs. -1 and 2, and has a closed upper end and an open lower end. The plunger is the block. The scale may be printed or engraved directly on the block but, preferably, a separate indicator plate 65 is provided for this purpose. It' is L-shaped in cross-section, as shown in Fig. 3, and is attached to the block by means of a set screw 66, Fig. 1, which extends through a slot 61 in the plate and is threaded into. the block 40. A washer 6B frictionally engages the outer edge of the indicator plate 65 and a spring 69 is provided between the head of the set screw and thewasher 68 for causing the washer 68 to fricadapted to be filled with porous or fibrous ma- 76 tionally hold the plate in vertically adjusted posjition. The indicator plate 55 is provided with a scale II; that is, it is calibrated so that the percentages may be read directly from the scale.

The testing liquid, which is caustic soda (NaOH) or potash (KOH) if CO2 is to be tested,

' is introduced into the instrument by removing the plug 25 and pouring the caustic solution into the receptacle 23- while holding the valve i9. in lowered position. Sufficient-liquid is introduced to bring the level thereof in the columns to a level Just. below the upper end wall 51 of the plunger but of sumcient distance from the upper end of the plunger to compensate for the rise of the column of caustic so that during tests none of the liquid will pass through the opening 50.

In the operation of, the device, the two valves l9 and 32 are first pressed down for opening the same forv placing the two columns in communication with the air for equalizing the pressure therein. The two valves may then be released.

After the flexible tube for conducting the gas to the instrument has been attached to the nipaccuse tionally engaging the walls of the surrounding pic 48 and proper connections made, the valve 19 is lowered by pushing downwardly on the fitting 46 against the compression of the spring 53 and the pump is operated for introducing the gas through the conduit 43 into the chamber 35. The gas passes into the chamber through the passage 43 and the air and gas pass out of the chamber 35 through the passage 44.

After the gas has been running through the chamber for some time so as to be sure to displace all of the air, the valve I9 is released for closing the passages 43 and 44 for entrapping a sample of the gas. Due to the small diameter of the passage in thethreaded extension of the plate 6|, the reading will not be affected. The operator will now raise and lower the plunger l4 by pulling upwardly and ,pushing downwardly on the knob 63 which will thoroughly mix the gas to be tested with the liquid. When the plunger is elevated, the gas will be forced through the passage 50 down into the wool where it is brought into intimate contact with the caustic. When the plunger is depressed, the caustic is forced upwardly into the wool for wetting the same. The reciprocation of the plunger is continued until-the liquid in the arm I3 becomes stationary when the plunger is seated on the shoulder Id.

The reaction of the caustic on the CO2 of the gas will lower the pressure within the chamber- 35 and cause the pressure of the air in the chamber 23 to force the liquid downwardly. inthe small bore l3 where the percentage may be read directly from the scale. In order to facilitate reading of the scale, the liquid maybe colored by aniline dye or the like. The lowering of the plunger IE will cause the wiper 62 to wipe the walls of the chamber 35 so that the chamber will be in condition for receiving the next charge.

bore, said'plunger and washer-having alined axial openings of small caliber, valve means through which a gas may enter or be discharged from the space withinsaid bore above said plunger, and a graduated scale carried by said block and positioned opposite the other bore for indicating the level of said solution therein.

3. An apparatus for indicating the amount of a particular gas constituent ina gas sample, comprising a block of material having .a U-shaped bore therein adapted to be partially filled with,

a liquid that will react on said gas constituent,

' one arm of said bore being of greater diameter greater diameter and frictionally engaging the While the members l2 and I3 are described as arms of a U-shaped bore, they may be regardedas two columns or receptacles connected together by a transverse bore it which places the two re- 7 ceptacles in communication with each other.

It is thought from the foregoing, taken in connection with the accompanying drawmg, that the construction and operation of my device will be apparent to those skilled in the art and that changes in size, shape, proportion and .detail may be made without departing from the spirit and scope of the appended claims. I claim as my invention: 1. A gas indicator comprising primary and secondary upstanding receptacles having their lower .ends connected together by a passage and being adapted to be partially filled witha liquid that in adapted to contain a caustic solution extending upwardly into both arms thereof, plunger open at its lower end and filled with a hollow mineral wool within one arm .of said U-shaped bore, meansincluding a lcnob on the plungerfor raising or lowering .said plunger into and out, of the surface 01'- the liquid in the said one of said arms, a washer carried by said plunger and frictransparent than the other, means for introducing the gas to be indicated into the arm of larger diameter above said liquid and for discharging the air fromsaid last-named arm, movable means for selectively separating said gas and liquid and for inter-mingling said gas sample and liquid, said means including a plunger within said .arm of walls of said last-named arm for preventing accumulation ofsolid matter-"thereon, said plunger being hollow and open at its lower end, the upper end ofsaid plunger being of solid material and having-a small aperture through which the gasto be tested may pass during the testing operation, spongelike material in the hollow of'said plunger, and means carried :by' said block adjacent the smaller bore for indicating the percentage of the particular gas in said sample.

4. An apparatus for indicating the amount of a particular gas constituent in a gas sample comprising a block of material having a U-shaped bore therein adapted to be partially filled with a liquid that will react on said gas constituent, a

passage for conducting a gas to be tested to one arm of said bore and a passage for discharging the. air contained in said one arm, a single slidable valve for opening and closing said passages,

movable, means including a plate for normally separating said gas and liquid and .for bringing saidgas and liquid in intimate contact, said plate having an aperture for the passage of the gas to be tested, said means frictionally engaging the,

interior ofthe walls of said one arm, and a scale carried by said block for indicating the height "bf the liquid in the other of said arms.

5. A gas indicator comprising a block of transparent material having a U-shaped bore therein adapted to contain a caustic liquid partially m1- lng both arms of said U-shaped bore, means.

slidable in said block for entrapping-a sample of combustion gas in the u r portion of one arm oi Said bore, slidable means insaid one arm including an apertured solid member for normally separating said gas and liquid and also including a hollow plunger having means for intermingling said liquid with said gas, and a scale mounted j on said block for indicating the'percentage of 00: gas in said sample by comparing the level or the depressed liquid in said other arm of as! bore with its original level. p

6. A small portablegas testing device com. prising a block or transparent material provided witha U-shaped bore for containingcaustic liquid, means including a single slidingvalve-for admitting gas into and permitting discharge of the displaced air from one arm of saidbore; means in said one arm comprising a plunger having an upperclosed end and-an open bottom and containing means to intermingle said 'gas and liquidwhcn the plunger is operated, a wiper carried by said plunger tor'trictiomllyengaging the interior surface of the walls oi said one arm, said plunger having a small passage through its upper closed end through which the gas to be tested is adapted to pass, said plunger constituting means for separating the gas and liquid prior to theoperation of said plunger, and means comprising ascale carried by said block for indicating the amount of gas absorbed by said liquid.

'7.'In 'a portable gas tester, a pair of receptacles for containing a caustic liquid, a passage be-' low the level of said liquid for interconnecting said receptacles, means including slidable valve mechanism for trapping a sample of combustion receptacle, said slidablemeans including a wiper for cleaning the walls of said last named receptacle and including also a hollow plunger having a closed upper end and containing finely divided material adapted to be submerged in said liquid, said closed end being apertured for admitting gas to intermingle with liquid carried by said finely divided material, and a scale associated with the other receptacle for indicatin the amount of said gas absorbed by said liquid.

8. In a gas indicator, a U-shaped receptacle having its arms extending upwardly, a plunger in one of said arms, said receptacle being reduced in diameter in the lower portion of the otherof said arms, a shoulder for limiting the downward movement of said plunger in said one arm, said plunger being hollow and having an upper closed end with a small aperture therethrough, fibrous material in said plunger, a wiper secured to the closed end of said plunger and having a small aperture therethrough in alinement with said small aperture in the plunger,

said wiper frictionally engaging the walls of said one arm, said aperture being just large enough to let the gas through when the plunger is raised but small enough to prevent any substantial passage otherwise, said receptacle being adapted 'to contain a caustic liquid having its surface adjacent to the plane of said closed end when said plunger'i seated on said shoulder, means for equalizing the air pressure in both of said arms in the space above said liquid and Y for trapping a sample of combustion gas in the space above said plunger, handle means connected to said plunger for raising and lowering said plunger for lntermingling said gas and liq uid, and a scale opposite the liquid in the other of said arms for indicating the height of the liquid therein.

9. A gas testing apparatus comprising a block having a U-shaped bore therein, said bore having one arm of enlarged diameter and its other arm of greatly restricted diameter at its lower end an being adapted to contain a caustic solution partially filling said bore, plugs in the upper ends of said arms, an intake/and an exhaust port in one of said plugs, slidable valve means for opening and closing saidports, a plunger in the arm of the bore 01' enlarged diameter, said plunger having an opening extending longitudinally thereof, the upper portion of said opening being just large'enough to let the gas through when the plunger is raised but small enough to prevent any substantial passage otherwise, an a'pertured wiper carried by said plunger for cleaning the walls of said bore above said plunger, and a scale mounted on said apparatus for indicating the amount of said gas absorbed by said liquid during a test.

FRANK W. DWYER. 

